Black azo dye.



UNi'rEn STATES merited May 12, 1903'.

ATENT OFFICE.

MYRTIL KAI-IN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OFELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEWV YORK.

BLACK AZO DYE.

SPECIFICATION forming part of Letters Patent No. 727,967, dated May 12,1903.

Application filed March 3,1903. Serial No. 145,990. (No specimens.)

vented a new and useful Improvement in Azo A Coloring-Matters; and I doherebydeclare the following to be an exact and clear description of myinvention.

My invention relates to the production of new and valuable azo dyestuffsby combining the diazo compounds of ortho-amidophenol sulfonic acidshaving the general formula:

as G6H2 2( sc n x (X meaning a hydrogen atom which can be replaced byhalogens, NO -SO H, or CH such as ortho-amidophenol sulfonic acids, or-

tho-amidocresol sulfonic acids, ortho-amidophenol-nitro-sulfonic acids,ortho-amidophenol-chloro-sulfonic acids, ortho-amidophenol disulfonicacids, or the like, with 2:6-amidonaphthol having the formula:

I W's L into boiling water and allowed to remain there until the wateris cold; The goods thus asso me a high degree of gloss and softness,and, according to the effect desired, the potting may be repeatedseveral times.

In carrying out my process practically I can proceed as follows, theparts being by The black shades thus obtained posweight: Nineteen partsoforthoamidopheno' para-,sulfonic acid having the formula:

| son;

are diazotized in the usual manner, and the resulting diazo compound isstirred into asolution of 15.9 parts of 2.6-amidonaphthol in an excessof caustic-soda lye, care being taken that the mixture is alwaysalkaline during the reaction. After being stirred for some time theexcess of caustic-soda lye is neutralized by means of hydrochloric acid,and the new dyestuff is precipitated by the addition of common salt,filtered off, and dried.

The new coloring-matter thus obtained is in the shape of the sodium saltwhen dry and pulverized a brownish-black powder soluble in water and inalcohol to a reddish-violet solution'and soluble in concentratedsulfuric acid of 66 Baum to a violet-red solution, a brownish-redprecipitate being obtained therefrom by the addition of ice. It dyeswool from acid-baths reddish-violet shades. By subsequently treating thedyed fiber with chromium compounds reacting as oxidizing agents-such aschromates, bichromates, or the like-the shades are changed to blackdistinguished for great fastness to the potting process. They alsoresist milling and washing and possess a great fastness against theaction of light.

Having nowdescribed my invention, what I claim is- V 1. Theherein-described new azo dyestuffs derived from ortho-amidophenolderivatives having the above-given formula and-2:6- amidonaphthol which,when in a dry state, are brownish-black powders soluble in water withfrom a reddish-violet to bluish-violet color turning blue on adding asolution of sodium carbonate and dyeing wool from acidbaths fromreddish-violet to blue shades turning black by a subsequent treatmentwith chromium compoundsreacting as oxidizing agents, substantially ashereinbefore described.

2. The herein-described new azo dyestuifi derived fromortho-amidophenol-para-sulfonic acid having the above-given formula and2:6-amidonaphtho1, which, in the shape of the sodium salt, is abrownish-black powder s01- uble in water and in alcohol with areddishviolet c0101; soluble in concentrated sulfuric acid of 66 Baumwith a violet-red color, a brownish-red precipitate being obtainedtherefrom by addition of ice; dyeing W001 from acid-baths reddish-violetshades which are changed to black by a subsequent treatment withchromium. compounds reacting as oxidizing agents, substantially asdescribed.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses.

MYRTIL KAHN.

Witnesses:

OTTO KoNIG, J. A. RITTERSHAUS.

